Seat

ABSTRACT

A seating unit for a vehicle, particularly an aircraft, that has a movable portion including a back rest, a seat pan and a leg rest, and a fixed portion having front and rear legs. The movable portion is movable between a fully reclined position and an upright position. A recess is disposed below the back rest and seat pan in the upright position, the recess constituting a foot-well for a person using another seat therebehind. Front and rear cross-members can be fixedly secured respectively to the lower ends of the front and rear legs, and are fixed to seat tracks provided in the vehicle. In one embodiment, the fixed portion includes two spaced rear legs that are positioned on opposing sides of the recess, and the rear cross-member can be fixedly secured to the lower ends of both of the rear legs.

This application is a division or Ser. No. 09/053,042 Filed Apr. 1, 1998now U.S. Pat. No. 5,992,798.

FIELD OF THE INVENTION

The present invention relates to a seat, and has particular reference toa passenger seat for use on a passenger vehicle, especially an aircraft.The present invention also embraces a passenger vehicle such, forexample, as an aircraft, that is equipped with one or more seats inaccordance with the invention.

BACKGROUND TO THE INVENTION

Passenger seats for use on aircraft, sea-going passenger ferries andluxury coaches comprise a seat pan and a reclinable back-rest.Generally, the seat pan is fixedly secured to a support frame that isanchored to a floor of the vehicle. A disadvantage of this arrangementis that as the back-rest is reclined, it impinges on the space of apassenger using a seat positioned behind the one being reclined. Somepassenger seats, particularly those which are used in the business-classand first class sections of passenger aircraft, additionally include aleg-rest that can be moved between a raised position and a loweredposition. Often, the back-rest reclining and leg-rest moving mechanismsare linked, so that as the back-rest is reclined from an uprightposition to a reclined position, the leg-rest is move towards the raisedposition. Whilst the additional comfort provided by the leg-rest isrecognised, a disadvantage with this arrangement is that when theleg-rest is raised, the space (or “foot well”) adjacent the floor underthe back-rest and seat pan of a seat in front of the one being reclinedcannot be properly utilised.

At the time of writing, there is a trend towards providing passengerseats in which the back-rest and leg-rest can be maneuvered to form asubstantially flat surface with the seat pan on which a passenger canlie down for sleeping. In some cases, where the seat pan is fixedlysecured to a support frame as previously mentioned, this is simplyachieved by allowing the back-rest and leg-rest to be respectivelyreclined and raised further than was the case previously, so as to besubstantially coplanar with the seat pan. Of course, this exacerbatesthe problems discussed above associated with the use of recliningseat-backs and lifting leg-rests, and requires the pitch betweenadjacent rows of seats to be substantially increased.

WO-A-96/18537 of British Airways Plc discloses a passenger seat for anaircraft that comprises a housing that can be fixedly secured to a cabinfloor of the aircraft, and a movable portion comprising a back-rest, aseat pan and a leg-rest. The seat pan is hinged to the back-rest and issupported at a point remote from the hinge by a trolley, which trolleyis adapted for translational movement on the cabin floor between aretracted position and an extended position relative to the housing. Amotorised screw-drive is fitted between the trolley and the housing fordriving the trolley between these two positions. Two spaced arms thatare attached to opposing sides of the seat pan each comprise a guidemember that is accommodated within a track formed in a respective sidewall of the housing. The track is shaped, so that as the trolley ismoved between the retracted and extended positions, the part of the seatpan adjacent the hinge to the back-rest is raised or lowered, so thatthe seat pan is pivoted about its mounting on the trolley throughpre-selected orientations. Each side wall of the housing furthercomprises an additional track that accommodates a second guide member,which guide member is fixedly secured to a respective side of theback-rest. The additional tracks are configured so that as the trolleyis moved between the retracted and extended positions, and the seat panis rocked about its mounting on the trolley, the back-rest isprogressively reclined between an upright position and a fully reclinedposition, with the recline angle of the back-rest portion at any givenposition of the trolley being defined by the position of the hingebetween the seat pan and back-rest and the position of the second guidemembers in their respective additional tracks.

The passenger seat of WO-A-96/18537 is arranged so that as the back-restis reclined the back-rest remains within the housing, so that it doesnot interfere with the space of a passenger using a seat behind the onebeing reclined. In the fully reclined position, the seat pan andback-rest are oriented such that they are substantially coplanar withone another to form a flat surface for a passenger to sleep on. Thepassenger seat of WO-A-96/18537 further comprises a leg-rest that ismounted pivotably on the trolley adjacent the seat pan mounting. Asecond motorised screw-drive is provided for moving the leg-rest betweena lowered position and a raised position in which the leg-rest issubstantially coplanar with the seat pan and back-rest to extend thesleeping surface.

The passenger seat of WO-A-96/18537, whilst it solves the problem of theback-rest being reclined into a space of another passenger, has a numberof serious disadvantages. First of all, the trolley used for supportingthe seat pan, and for driving the movable part of the seat between theretracted and extracted positions is a complex, and thus expensivecomponent to manufacture and adds substantially to the weight of theseat. Secondly, as the seat pan is supported on the trolley remote fromthe hinge to the back-rest, the height of the seat pan where it ismounted on the trolley above the cabin floor is fixed. Thus, a foot wellprovided in the rear of a seat in front of the one being reclined cannotbe utilised fully when the seat is in the fully reclined position, withthe leg-rest raised.

A further disadvantage of the seat of WO-A-96/18537 is that thescrew-drive mechanism used for driving the trolley into and out of thehousing is located within the housing, beneath the seat pan andback-rest, in juxtaposition with the cabin floor. The screw-drivemechanism thus impinges on the space towards the bottom of the housingwhich is available for use as a foot well, and moreover is positionedwhere it is likely to collect dust, dirt and other detritus which may,in time, be injurious to proper operation of the screw-drive mechanism.

OBJECTS OF THE INVENTION

Accordingly, it is an object of the present invention to provide animproved seat for a passenger vehicle, in particular an aircraft.

Another object of the present invention is to provide a passenger seathaving a back-rest, seat pan and leg-rest, which seat can be maneuveredbetween an upright position and a fully reclined position in which theseat pan, back-rest and leg-rest define a substantially flat surface forsleeping on, which seat does not impinge on the space of a passengerusing a seat behind the one being reclined, and which enables the pitchbetween neighbouring rows of seats to be minimised.

Yet another object of the present invention is to provide a passengerseat in which, in the fully reclined position, the leg-rest ispositioned adjacent a floor of the vehicle, so as to make best use of afoot well provided in a seat in front of the one that is fully reclined.

Yet another object of the invention is to provide a passenger seat thatis light-weight, and is of uncomplicated construction.

Yet another object of the present invention is to provide a passengerseat in which the foot well space defined by the seat is maximised.Finally, it is yet another object of the invention to provide a seathaving a driving mechanism for driving the seat between upright andfully reclined positions, which driving mechanism is protected fromdirt, detritus and the like.

SUMMARY OF THE INVENTION

According to one aspect of the present invention therefore there isprovided a seat for a passenger vehicle, particularly an aircraft, whichseat comprises a first fixed part for supporting the seat adjacent afloor of a vehicle; a second movable part comprising a seat pancomponent, a back-rest component and a leg-rest component; guiding meansbetween the first fixed and second movable part for guiding movement ofthe movable parts relative to the fixed part between an upright positionand a fully reclined position, such that as the movable part is movedtowards the fully reclined position, said back-rest component is loweredtranslationally towards the floor; reclining means for reclining theback-rest component from an upright orientation to a fully reclinedorientation as the movable portion is moved from the upright to thefully reclined positions; first pivot means for allowing the leg-restcomponent to be pivoted relative to the seat pan component between araised position and a lowered position; and second pivot means forallowing the seat pan component to be pivoted relative to the back-restcomponent; characterised in that a locking drive means is associatedwith one of said first and second pivot means for pivoting relative toeach other the components pivoted on said one pivot means, free pivotingis allowed of the components pivoted about the other pivot means andcontrolling means are provided for controlling the operation of thelocking drive means according to the position of the movable partbetween the upright and the fully reclined positions; the arrangementbeing such that as the movable part is moved between the upright andfully reclined positions, the locking drive means is controlled suchthat the leg-rest component remains in contact with the vehicle floor.

Preferably the locking drive means acts between the seat pan andleg-rest components, and the leg-rest components and seat pan arecapable of freely pivoting relative to each other. It will beappreciated that as the movable part is moved progressively from theupright position to the fully reclined position, the guiding means guidethe movement such that the back-rest component is loweredtranslationally towards the floor of the vehicle. As the back-restcomponent is lowered towards the floor, the recline angle of theback-rest component is controlled by the reclining means. As the seatpan component is capable of pivoting freely with respect to theback-rest component, it will be understood that the effect of loweringthe back-rest component translationally towards the floor of the vehiclewill be to cause the seat pan component to tilt rearwardly, that is toreduce the angle subtended by the back-rest and seat pan components tothe side of the movable part which is intended to be sat on by apassenger, that is the upper side. However, the orientation of the seatpan component will also be affected by the angle between the leg-restand seat pan components which can be adjusted by the locking drivemeans.

In accordance with the present invention, the seat is operated, so thatthe leg-rest component remains in contact with the vehicle floor. As theangle subtended by the leg-rest and seat pan components to the underside of the movable part is increased by operating the locking drivemeans, so as to move the leg-rest component towards the raised position,the seat pan component will therefore tend to tilt forwardly, that is toincrease the angle subtended by the back-rest and seat pan components tothe upper side of the movable part. The actual orientation of the seatpan component is thus defined by the position of the back-rest componentbetween the upright and fully reclined positions, and by the position ofthe leg-rest component between the raised and lowered positions.

Preferably therefore the guide means, reclining means and locking drivemeans will be constructed and operated, so that as the movable part ismoved between the upright and fully reclined positions, the back-rest,seat pan and leg-rest components are moved through one or morepre-determined, ergonomically comfortable positions in succession.Intermediate these pre-selected positions, the construction and controlof the guiding means, reclining means and controlling means can becalculated by interpolation.

In some embodiments, the back-rest, leg-rest and seat pan componentswill define a substantially flat surface for a passenger to sleep on,when the movable part is disposed in the fully reclined position.

Said leg-rest component may be equipped with a linear bearing such, forexample, as rollers or casters, for facilitating movement of theleg-rest component over the floor of the vehicle.

In a particularly preferred aspect of the present invention, the lockingdriving means acts between the seat pan and leg-rest components, so thatthe leg-rest component can be used to support at least part of theweight of the movable part of the seat (and passenger when the seat isin use) on the floor of the vehicle. It will be appreciated that asubstantial part of the weight of the movable part and passenger that issupported by the back-rest and seat pan components will be transmittedto the leg-rest component through the locking drive means. At eachposition of the movable part between the upright and fully reclinedpositions, the locking drive means serves to hold the seat pan andleg-rest components in fixed relation to one another. As the leg-restcomponent is supported on the floor of the vehicle, the seat pancomponent is thus unable to move rotationally or translationally, thuspreventing movement of the back-rest component. The combination of thelocking driving means between the seat pan and leg-rest components, andthe leg-rest component being held in contact with the vehicle floor,thus serves to hold the movable part of the seat in the selectedposition.

It is envisaged that the locking drive means may comprise a screw-drivemechanism.

It is also envisaged that the leg-rest component will usually be pivoteddirectly to the seat pan component, and the seat pan component will bepivoted directly onto the back-rest component.

Usually, the seat accordingly to the present invention will furthercomprise selectively operable driving means for driving the movable partprogressively between the upright and fully reclined positions.

Said guiding means will preferably comprise at least one elongate trackthat is provided on the fixed part of the seat, and a track followingmember provided on the back-rest, which track following member engagesthe track for guiding the movable part between the upright and fullyreclined positions.

Preferably, the back-rest component will be equipped with a second trackfollowing member that also engages the track, and is spaced from thefirst-mentioned track member along the length of the track, and thetrack itself may be configured, so that at each position of the movablepart between the upright and fully reclined positions, the back-restcomponent will be located relative to the track at two spaced positions,thus defining the recline angle of the back-rest component.

Said fixed part will preferably comprise two tracks positioned onopposing sides of the movable part, and the back-rest component will beequipped with two spaced guide following members to each side, so thatthe two guide following members to each side engage with the respectivetrack as previously described. Said guide following members may berollers or other linear bearings.

In some embodiments, at least one, and preferably both of the tracks arefitted with a rack, and one of the first or second guide followingmembers includes a pinion that engages with the rack. Preferably, saidselectively operable driving means comprises a locking drive mechanismthat is arranged for driving the pinion, so as cause or allow movementof the movable part of the seat between the upright and fully reclinedpositions. Said locking drive mechanism may comprise a selectivelyoperable motor, which motor is preferably mounted on the back orunderside of the back-rest component. Said motor may be arranged todrive an axle that extends across the back-rest component between thetwo sides of the movable part, and each end of the axle may carry apinion that engages in a respective rack. Said racks may be manufacturedfrom steel, aluminium or a suitable, high-strength plastics or compositematerial that can be shaped to follow the pre-determined configurationof the track.

The mounting of the motor on the back of the back-rest component awayfrom the floor is advantageous, because the motor is protected fromdust, dirt and detritus. Moveover, the motor mounted on the back-restcomponent in accordance with the present invention does not occupy spacetowards the bottom of the seat, thereby allowing more room for afoot-well.

Said fixed part may comprise a shaped housing having a back-wall and twoopposing side walls. Said tracks may be formed in or carried by the saidside walls of the housing.

It is envisaged that said controlling means may comprise detecting meansfor detecting the position of the movable part between the upright andfully reclined positions, a memory for storing the desired position ofthe locking driving means for each position of the movable part, and amicroprocessor for controlling operation of the locking driving means inresponse to input from the detecting means and the memory.

Said controlling means may be adapted to operate the driving means andthe locking driving means at constant or varying speeds independently ofeach other. In a preferred embodiment the driving means is operated at aconstant speed, and the locking driving means at varying speeds.

Following is a description by way of example only with reference to theaccompanying drawings of methods of carrying the present invention intoeffect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric front view from above and to one side of a seatunit comprising two passenger seats in accordance with the invention.

FIG. 2 is an isometric rear view from above and to the one side of theseat unit of FIG. 1.

FIG. 3 is an isometric view of the housing for the seat unit of FIGS. 1and 2.

FIG. 4 is a side view of a single seat in accordance with the presentinvention, which seat is disposed in an upright position.

FIG. 5 is a side view, partly in cross-section, of a foot fixing.

FIG. 6 is a bottom view of the foot fixing of FIG. 5.

FIG. 7 is a front view of the foot fixing in the direction of the arrowlabelled III in FIG. 5.

FIG. 8 is an end view, partly in cross-section, of a seat unit inaccordance with the present invention.

FIG. 9 is an isometric view from behind of the back-rest of the seat ofFIG. 4, shown separated from the rest of the seat.

FIG. 10 is a rear elevation, partly in cross-section along the linesVI—VI of FIG. 9, of the drive mechanism for driving the seat within thehousing.

FIG. 10A shows a detail of part of the drive mechanism of FIG. 10.

FIG. 11 is a side elevation of the back-rest of FIG. 9.

FIG. 12 is a side view of the seat of FIG. 4, shown in a first reclinedposition.

FIG. 13 is a side view of the seat in FIG. 4 shown in a second reclinedposition.

FIG. 14 is a side view of the seat in FIG. 4 shown in a fully reclinedposition.

FIG. 15 is a side view of two single seats according to the invention,one positioned behind the other.

FIG. 16 is a graph of the linear extension of the locking screw-drivebetween the seat pan and leg-rest of the seat of FIG. 4 versus thenumber of rotations of the electric motor for driving the back-rest.

DETAILED DESCRIPTION OF THE DRAWINGS

A seat unit as illustrated in FIGS. 1 and 2 comprises two adjacent seathousings (10,10′) as shown in FIG. 3 that can be fixedly secured to afloor (F) of a vehicle such, for example, as a passenger aircraft. Eachhousing (10,10′) accommodates a movable part that comprises a seat pan(20), a back-rest (22) and a leg-rest (24).

Said housing (10) comprises spaced, upstanding inner and outer sidewalls (14,16) and a shaped rear wall (12). Said rear wall (12) and sidewalls (14,16) may be manufactured from any suitable, light-weightstructural material, but preferably they comprise an aluminium andpressure moulded composite skeleton frame (15) and a cladding mouldedfrom a plastics or glass/resin composite material. The side walls(14,16) and rear wall (12) define a recess (18) that accommodates themovable part of the seat, such that the rear wall (12) is disposedbehind the movable part as shown in FIG. 1.

Each of the outer side walls (14) is fitted with an arm-rest (26), andthe juxtaposed inner side walls (16) of the two housings are joined by acentre amenities arm-rest (27). Each side wall (14,16) is shaped towardsit lower end to define a front leg portion (17). A thin, rigid plate(28) which may be made from extruded aluminium, light steel or astructural composite material extends between the two front leg portions(17) as shown in FIG. 3, and is drilled (not shown) for fixing thehousing (10) in position. Passenger seats for use on aircraft areusually secured to spaced, parallel seat tracks provided in a floor of apassenger cabin of the aircraft, and where the seat unit of the presentinvention is intended for use as an aircraft passenger seat therefore,the plate (28) may be equipped with suitable fixings to seat tracks.Seat fixings of the kind disclosed in copending UK patent applicationno. 9803122.2, the contents of which are incorporated herein byreference, are preferred.

For additional support, the housing (10) is further provided with twospaced rear leg portions (30), and a second plate (32) is carried by therear leg portions (30) to provide additional rigidity and attachmentpoints to the seat tracks. A carpet (C) will usually be laid on thevehicle floor, and this abuts the first-mentioned and second plates(28,32). Plate 32 is protected from wear and damage by a plasticdecorative cover.

As seen in side view in FIG. 4, the rear wall (12) extends generallyvertically behind the back-rest (22) of the movable part of the seat,and extends downwardly and forwardly under the seat pan (20) to meet thefloor (F) forwardly of the first plate (28). Said rear wall (12) withthe front and rear leg portions (17,30) thus defines a recess (34)beneath the back-rest (22) of the seat pan (20), which recessconstitutes a foot-well for a person behind the seat.

In accordance with UK patent application no. 9803122.2, with referenceto FIGS. 5, 6 and 7, a foot fixing (110) comprises a foot blockcomponent (112) and a plunger component (142). Said foot block component(112) is made as a single piece from a steel alloy that is suitable foruse in aircraft constructions. Said alloy should be non-brittle andcapable of deformation when subjected to high loads. In the embodimentsshown in the drawings, steel alloy reference S143 is employed.

Said foot block component (112) comprises a track engaging portion (114)that is generally frustoconical in side view and has a flat bottomsurface (116) at its widest part. Said flat bottom surface (116) isgenerally dumb bell shaped, defining two, generally circular studportions (118), the centres of which are spaced apart from one anotheron a longitudinal axis indicated by the dashed line (120) in FIG. 6.

The narrower end of the track engaging portion (114) extends away fromthe flat bottom surface (116) and meets a narrow, waisted portion (122)that has the form of an elongate blade as shown clearly in FIG. 7. Saidblade is oriented substantially parallel to said longitudinal axis(120). The length of the blade portion along the longitudinal axis, isabout 25 mm, and its height, perpendicular to the longitudinal axis isabout 5 mm. The thickness of the blade, orthogonal to the longitudinalaxis (120) and in parallel to the plane of the flat bottom surface(116), is about 15 mm at the narrowest part.

Remote from the track portion (114), the blade portion (122) is joinedto a circular disc portion (124), which disc portion (124) carriesthereon a slider portion (126) having a T-shaped section in a planeorthogonal to the flat bottom surface (116) of the track engagingportion (114), as shown in FIG. 5.

In plan view, said slider portion (126) is generally oval in outline asshown in FIG. 6, and the major axis of the oval shape is orientedsubstantially orthogonally to the longitudinal axis (120). Said sliderportion (126) is drilled either side of the blade portion (122) toprovide two spaced open bores (128), each of which open bores (128)accommodates a fixing screw (130) for fixing the slider portion (128) toa vehicle seat in a manner as described hereinafter.

The centres of the two generally circular studs (118) are spaced apartby about 2.54 cm (1 inch), so that the studs can be inserted through thecoin shaped slots formed in an aircraft seat track of the kind wellknown to those skilled in the art.

The track engaging portion (114) of the foot block component (112)further comprises a protruding lug (132) that extends on saidlongitudinal axis (120). Said lug portion (132) is drilled at (134) toaccommodate a pin (136) of a clevis connector (138) of said plungercomponent (142). The joint between the clevis connector (138) and thelug (132) allows the plunger component (142) to be pivoted on the pin(136) with respect to the foot block component between a releasedposition as shown in dashed lines in FIG. 5 and a fitted position asshown in solid lines. As can be seen from FIG. 5, said clevis connector(138) is formed with a integral protrusion (139) that forms a cam. Inthe fitted position of the plunger component (142), the protrusion (139)extends downwardly below the bottom surface (116) of the foot blockcomponent (112). Said protrusion is shaped such that as the plungercomponent (142) is pivoted to the fitted position, the protrusion (139)engages the seat track and by a camming action pushes downwards on thetrack, which in turn urges or “jacks” the foot block component (112)upwards into engagement with the flanges forming the slot in the track.This causes the footblock component (112) to be jammed firmly in thetrack, thus preventing rattle of the components in the track afterinstallation.

Said clevis connector (138) is formed on one end of an elongate ribportion (144) that extends from the foot block component (112) on saidlongitudinal axis (120). Said rib portion (144) carries a depending stud(146) of circular cross-section and a generally flat, rectangular webportion (148). The centre of the depending stud (146) is spaced from thecentres of the stud portions (118) on the foot block component (114) byn×12.7 mm, where n is an odd number. Juxtaposed the stud (146), the ribportion (144) is drilled at (150) to accommodate a screw (152). The hole(150) is countersunk to accommodate the head of the screw (152), whichscrew protrudes from the rib portion (144) and carries at its other enda key (154) that is keyed onto the stem of the screw (150).

In order to fix the seat unit to a seat track, the slider portion (126)of the foot block component (112) is secured to the seat unit asdescribed below. With the plunger component (142) in the releasedposition, the track engaging portion (114) is entered into the seattrack, such that the two studs (118) enter two neighbouring coin slotson the track. The foot block component (112) (and attached seat unit) isthen displaced along the track by 12.7 mm (½″), so that the studs (118)are engaged in the seat track. The plunger component (142) is thenpivoted about the clevis connection, so that the stud (146) entersanother coin slot on the track, and the web portion (148) lies flushacross the top of the track. The screw (152) is then turned, so that thekey (154) engages the inner side walls of the track to preventlongitudinal movement of the foot fixing (110) with respect to the seattrack.

In the event of an excessive load being applied between the seat unitand the seat track (e.g. in the event of a collision) the blade portion(122) is capable of deforming to absorb some of the energy of theimpact, so as to direct energy away from the body of a passenger usingthe seat.

As shown most clearly in FIG. 3, the lower ends of the rear legs (30) ofthe two seats (10,10′) of the seat unit are fixedly secured to anelongate plate (32). Similarly, the stub front legs (17) of the twoseats (10,10′) are attached to a second plate (28). Each of said plates(32,28) is cut from a length of extruded, pressed aluminium. Each ofsaid plates (32,28) has a substantially flat underside (194) which isformed with an elongate channel (196), which channel extends into thebody of the plate. Said channel (196) is generally T-shaped incross-section and is shaped to accommodate the slider portions (126) ofone or more foot fixings of the kind described above.

For each of the plates (32,28), the required number of foot fixings(110) are slid into the channels (196) depending on the number seattracks to which the seat unit is to be anchored. As shown in FIG. 8, itis usually the case that each seat unit is to be secured to two spacedseat tracks (100). As can further be seen from FIG. 8, each of the seattracks (100) is positioned more or less centrally with respect to thefoot well (34) of a respective one of the seats (10,10′). Thus, two footfixings (110) are engaged with each of the plates (32,28), and thesefoot fixings (110) slid along the channels (196) in the plates (32,28)until the foot fixings are positioned in alignment with the seat tracks(100). The foot fixings can then be fastened to the plates (32,28) bymeans of the two screws (130) in each fixing (110). Each fixing (110) isthen secured to a respective seat track (100) in the manner describedabove.

It will be appreciated by those skilled in the art that the seat unit ofthe present invention can thus be secured to two or more seat tracks inany aircraft (or vehicle), and at any location on that aircraft, becausethe position of the foot fixings (110) can be adjusted according to thespacing of the seat tracks (100). Moreover, the assembly of the plates(32,28) with the foot fixings (110) provides a very low level anchoragebetween the seat tracks and the seat unit which does not constitute asignificant trip hazard, and moreover allows the leg-rest portion (24)of a seat located behind the seat unit in question to be extended intothe foot well (34) so as to optimise the use of space on the vehicle.

A further advantage of the foot fixing (110) and seat unit of thepresent invention is that a positive engagement can be provided at boththe front and rear ends of the seat by means of a shear plunger whichresists longitudinal movement of the seat unit along the seat tracks.The inherent flexibility of the legs (30,17) allows the spacing betweenthe two plates (32,28) to be adjusted slightly, so that the plungers ofthe foot fixings secured to both plates (32,28) can be properly alignedwith coin slots in the seat tracks. It will be noted by those skilled inthe art that the seat unit of the present invention does not include anystiffening frame components between the front and rear legs (30,17) injuxtaposition with the vehicle floor.

The seat unit of FIGS. 1 and 2 comprises two adjacent passengerplacements. It is also envisaged that individual seats comprising singlepassenger placements may be provided in accordance with the invention,and for convenience the operation of the seat of the invention isfurther described with reference to the single seat shown in FIGS. 4 and12 to 15.

Said back-rest (22), on its rear surface (36), carries a locking driveunit (38) (see FIGS. 5 and 6), which locking drive unit comprises anelectric motor (40), having an output that is coupled through a gear box(42) to two, coaxial drive shafts (44). Each drive shaft (44) extendssubstantially horizontally between the gear box (42) and a respectiveside (46) of the back-rest (22). Each drive shaft (44) is journalled ina rotational bearing (48) which is mounted on the back of the back-rest(22) juxtaposed said respective side (46). The drive shaft (44)protrudes beyond the side (46) of the back-rest (22) and carries aroller bearing (50) and a pinion (52) that is keyed onto the end of thedrive shaft.

Said pinion (52) and roller bearing (50) on each drive shaft (44) areaccommodated in a track (54) formed in the adjacent side wall (14,16) ofthe housing (10). Said track (54) is formed as a channel which isdefined by two opposing surfaces (55) and, in cross-section as shown inFIG. 10, has a relatively narrow inner portion (56) that accommodatesthe roller (50), and a relatively wider outer mouth portion (58) thataccommodates the pinion (52), which roller bearing (50) engages onesurface (55) of the inner portion (56). One surface of the outer portion(58) is fitted with an elongate rack (60), which rack is engaged by thepinion (52). Operation of the motor (40) thus causes rotation of the twodrive shafts (44) and pinions (52), and the inter-engagement of thepinions (52) with the racks (60) causes translational movement of thepinions along the racks, thus resulting in movement of the movable partof the seat relative to the housing (10).

Said gear box (42) can be controlled, so as to reverse the direction inwhich the drive shafts (44) are driven. Accordingly, the movable part ofthe seat can be driven in either direction along the tracks (54).Passenger-operable controls for the drive unit (38) may be provided at aconvenient location on the seat, and in this connection it is envisagedthat such controls will usually mounted in the arm-rest portions (26) orthe central amenities arm-rest (27). By operating the controls, apassenger using the seat can move the movable part to any selectedposition along the track (54), and once the selected position has beenreached, the drive unit will be self-locking so as to prevent freerotation of the drive shafts (44) and concomitant, unwanted movement ofthe movable part of the seat.

Each of said tracks (54) also accommodates a guide roller (62) that isjournalled in a bearing (64) mounted on the back of the back-rest (22)at a point spaced from the roller bearing (50) and pinion (52)accommodated in the same track (54). The two guide rollers (62) arepreferably mounted coaxially with one another as shown in FIG. 9, andeach guide roller (62) engages one surface (55) of the inner portion(56) of the respective track (54), and thus serves positively to locatethe back-rest at a second point in the track (54). It will beappreciated therefore that the orientation of the back-rest will bedefined by the positions of the first-mentioned roller bearings (50) andthe guide rollers (62), and these positions in turn will be defined bythe configuration of the tracks (54).

Said tracks (54) are configured identically to one another and, as willbe seen from FIG. 4, are shaped so that as the pinions (52) are movedfrom a first upper end (66) towards a second lower end (68), theback-rest (22) is moved from an upright position as shown in FIG. 4 to afully reclined position as shown in FIG. 14, through one or morepre-selected, intermediate reclined positions. The seat illustrated inthe figures is designed, so that the back-rest (22) passes through twosuch intermediate positions shown respectively in FIGS. 8 and 9. Theconfiguration of the tracks (54) can thus be calculated by determiningthe required relative positions of the roller bearings (52) and guiderollers (62) at the upright, intermediate and fully reclined positions,and between these pre-selected positions, the location of the tracks(54) is calculated by interpolation.

Said seat pan (20) is hinged on the back-rest (22) and leg-rest (24) byhinges (23) and (25) respectively, and a locking screw-drive mechanism(70) is connected between an underside of the seat pan (20) and an underside of the leg-rest (24). Said locking screw-drive mechanism (70) isused to control the angle subtended by the seat pan (20) and leg-rest(24), and is connected to a control device (not shown) for controllingthe operation of the locking screw-drive mechanism (70) in response tothe position of the movable part along the tracks (54). Whilst many waysof achieving this control will be readily apparent to a person skilledin the art, in the embodiment shown the control device comprises amicroprocessor that receives input from a detecting device (such as apotentiometer linked to the electric motor (40)) for detecting theposition of the pinions (52) along the tracks (54), and a memory devicefor storing the desired positions of the locking screw-drive mechanism(70) for each positions of the pinions (52), the output of themicroprocessor being used to control the operation of the lockingscrew-drive mechanism (70). Said locking screw-drive mechanism (70)operates to adjust the angle subtended by the seat pan (20) and leg-rest(24) in response to the output of the controlling device and, at eachselected position, to hold the seat pan (20) and leg-rest (24) securelyin that position.

FIG. 16 shows a graph of the linear extension of the locking screw-drivemechanism (70) in relation to the number of revolutions of the electricmotor (40) from the upright position (UP) to the fully reclined position(FR). It will be seen that in this presently preferred embodiment, theoperation of the locking screw-drive mechanism (70) comprises threepositions where the mechanism remains stationary for a small,predetermined number of rotations of the electric motor, and thatintermediate these positions the speed of the mechanism (70) isapproximately constant.

Said leg-rest (24) extends downwardly from the seat pan (20), and isfitted at its lower end with a full width roller (72) that engages thefloor (F) of the vehicle. It will be appreciated that as the seat pan(20) is able to pivot freely with respect to the back-rest (20), theweight of the seat pan (20), leg-rest (24) (and a passenger when theseat is in use) will hold the leg-rest (24) in engagement with the floor(F), and the leg-rest (24) thus serves to support a substantial part ofthe weight of the movable part of the seat and passenger.

It will also be appreciated that the locking screw-drive mechanism (70)can be used to control the orientations of the seat pan (20) andleg-rest (24) relative to the back-rest (22) for any given position ofthe pinions (52) along the tracks (54). As the pinions (52) are drivenalong the tracks, the back-rest (22) is moved progressively,translationally downwards and forwards as described above. If thelocking screw1 drive mechanism (70) remains fixed, then this downwardsand forwards movement of the back-rest (22) will cause concomitantforward movement of the seat pan (20) and leg-rest (24), and will alsocause the seat pan (20) to tilt rearwardly with respect to the back-rest(22), so as to reduce the angle subtended by the upper surfaces of theback-rest (22) and seat pan (20). On the other hand, if the lockingscrew-drive mechanism is extended, then the angle subtended by theunder-sides of the seat pan (20) and leg-rest (24) is increased, whichhas the effect of lowering the leg-rest (24) from an upright position asshown in FIG. 4 towards an extended position as shown in FIG. 14, andcausing the seat pan (20) to tilt forwards. Thus by carefully designingthe configuration of the tracks (54), and controlling the operation ofthe locking screw-drive mechanism (70), the orientations of the seat pan(20) and leg-rest (24) at each of the pre-selected positions of theback-rest (22) can be chosen, and again, intermediate these positions,the orientations of the seat pan (20) and leg-rest (24) can bedetermined by interpolation. Preferably, in each of the pre-selected,upright, intermediate reclined and fully reclined positions as shownrespectively in FIGS. 4, 8, 9 and 10 of the drawings, the back-rest(22), seat pan (20) and leg-rest (24) define pre-selected, ergonomicallycomfortable positions for a passenger using the seat. In the seatillustrated in the drawings, the seat pan (20), back-rest (22) andleg-rest (24), are substantially coplanar with one another in the fullyreclined position as shown in FIG. 14, so as to provide a substantiallyflat surface for a passenger to sleep on. Said substantially flatsurface may subtend an angle of about 12° or 13° (angle α in FIG. 14)with the floor (F). As aircraft generally fly at a pitch of about 3°, ofthe actual inclination of the flat surface to the horizontal in flightwill be about 9° to 10°.

As shown in FIG. 11, seats in accordance with the present invention maybe arranged in vehicle such that one seat (A) is located behind another(B), such that when the one seat (A) is moved to the fully reclinedposition as shown in FIG. 11, the leg-rest (24) extends into thefoot-well space (34) defined by said other seat (B). As shown in FIG.11, when the one seat (A) is moved to the fully reclined position, thelower end of its leg-rest (24) is disposed adjacent the lower end of therear wall (12) of the other seat (B), thereby minimising the pitchbetween the seats (A,B).

It is envisaged that seats in accordance with the present invention willusually be manufactured as seat units, each seat unit comprising twoseats side-by-side as shown in FIGS. 1 and 2.

An advantage of the seat as hereinbefore described is that it can bemanufactured with a light-weight, relatively uncomplicated manufacture,and does not require the use of trolleys or the like for supporting theseat pan and leg-rest off the floor. In the fully reclined position, theleg-rest is positioned in juxtaposition with the floor, which enablesfull use to be made of the foot-well of a seat in front of the one thatis reclined.

Furthermore, as the seat pan is supported by the leg-rest, the only“dead-space” occupied by the seat in the upright position is thethickness of the rear wall (12) and the leg-rest (24) of the seat, thereminder of the space, fore and aft of the rear wall (12) and leg-rest(24) can be used respectively by a passenger using the seat, and apassenger using the seat behind.

Positioning the drive unit for the movable part of the seat on the backof the back-rest (22) represents a convenient solution to the problemreducing the useful space that is occupied by such a drive unit, andmoveover by positioning the drive unit on the back of the back-rest (22)the drive unit is spaced from the floor of the vehicle where dirt, dustand detritus are likely to collect.

What is claimed is:
 1. A seating unit for a vehicle, particularly anaircraft, said seating unit comprising: a movable portion comprising aback rest, a seat pan and a leg rest, which movable portion is movablebetween a fully reclined position and an upright position; a fixedportion having front and rear legs, each of said front and rear legshaving a lower end, and defining a recess disposed below the back restand seat pan in the upright position, said recess constituting afoot-well for a person using another seat therebehind; front and rearcross-members that can be fixedly secured respectively to the lower endsof the front and rear legs; fixing means for fixing each of saidcross-members to seat tracks provided in the vehicle; wherein said fixedportion comprises two spaced rear legs that are positioned on opposingsides of the recess; and wherein said rear cross-member can be fixedlysecured to the lower ends of both of said rear legs.
 2. A seating unitas claimed in claim 1, wherein said fixed portion comprises a pluralityof rear legs, and said rear cross-member is adapted to be secured to thelower end of each rear leg.
 3. A seating unit as claimed in claim 1,wherein said fixed portion comprises a plurality of front legs, and saidfront cross-member is adapted to be secured to the lower end of eachfront leg.
 4. A seating unit as claimed in claim 1, wherein said fixedportion comprises a plurality of front legs and a plurality of rearlegs.
 5. A seating unit as claimed in claim 3, wherein said frontcross-member is detachable from the lower end of each front leg.
 6. Aseating unit as claimed in claim 1, wherein each of said front and rearcross-members is adapted to be secured to two substantially parallelseat tracks in the vehicle by two foot fixings.
 7. A seating unit asclaimed in claim 1, further comprising guiding means between the fixedportion and the movable portion for guiding movement of the movableportion relative to the fixed part between said upright position andsaid fully reclined position, such that as the movable portion is movedtowards the fully reclined position, said back-rest is loweredtranslationally towards the floor; reclining means for reclining theback-rest from an upright orientation to a fully reclined orientation asthe movable portion is moved from the upright to the fully reclinedpositions; first pivot means for allowing the leg-rest to be pivotedrelative to the seat pan between a raised position and a loweredposition; and second pivot means for allowing the seat pan to be pivotedrelative to the back-rest; wherein a locking drive means is associatedwith one of said first and second pivot means for pivoting relative toeach other the components pivoted on said one pivot means, free pivotingis allowed of the components pivoted about the other pivot means andcontrolling means are provided for controlling the operation of thelocking drive means according to the position of the movable partbetween the upright and the fully reclined positions; wherein as themovable portion is moved between the upright and fully reclinedpositions, the locking drive means is controlled such that the leg-restremains in contact with the vehicle floor.
 8. A seating unit as claimedin claim 7, wherein the guiding means, reclining and locking drive meansare constructed and operated, so that as the movable portion is movedbetween the upright and fully reclined positions, the back-rest, seatpan and leg-rest are moved through one or more predetermined,ergonomically comfortable positions in succession.
 9. A seating unit asclaimed in claim 7, wherein the back-rest, leg-rest and seat pan definea substantially flat surface for a passenger to sleep on, when themovable portion is disposed in the fully reclined position.
 10. Aseating unit as claimed in claim 7, wherein said leg-rest comprises alinear bearing for facilitating movement of the leg-rest over the floorof the vehicle.
 11. A seating unit as claimed in claim 7, furthercomprising a selectively operable driving means for driving the movableportion progressively between the upright and fully reclined positions.12. A seat as claimed in claim 11, wherein said guiding means comprisingat least one elongate track that is provided on the fixed portion of theseat, and a track following member provided on the back-rest, whichtrack following member engages the track for guiding the movable portionbetween the upright and fully reclined positions.
 13. A seat as claimedin claim 12, wherein the back-rest is equipped with a second trackfollowing member which also engages the track, and is spaced from thefirst mentioned track member along the length of the track, and thetrack is configured, so that at each position of the movable portionbetween the upright and fully reclined positions, the back-rest islocated relative to the track at two spaced locations, thus defining therecline angle of the back-rest.
 14. A seating unit as claimed in claim11, wherein the selectively operable driving means comprises a motorthat is mounted on the back of the back-rest.
 15. A seating installationfor a vehicle, particularly an aircraft, said seating installationcomprising first and second seating units that are positioned one behindthe other; wherein each seating unit comprises: a movable portioncomprising a back rest, a seat pan and a leg rest, which movable portionis movable between a fully reclined position and an upright position; afixed portion having front and rear legs, each of said front and rearlegs having a lower end, and defining a recess disposed below the backrest and seat pan in the upright position, said recess constituting afoot-well for a person using another seat therebehind; front and rearcross-members that can be fixedly secured respectively to the lower endsof the front and rear legs; and fixing means for fixing each of saidcross-members to seat tracks provided in the vehicle; wherein said fixedportion comprises two spaced rear legs that are positioned on opposingsides of the recess; and wherein said rear cross-member can be fixedlysecured to the lower ends of both of said rear legs.
 16. A seatinginstallation as claimed in claim 15, wherein each seating unit furthercomprises guiding means between the fixed portion and the movableportion for guiding movement of the movable portion relative to thefixed portion between an upright position and a fully reclined position,such that as the movable portion is moved towards the fully reclinedposition, said back-rest is lowered translationally towards the floor;reclining means for reclining the back-rest from an upright orientationto a fully reclined orientation as the movable portion is moved from theupright to the fully reclined positions; first pivot means for allowingthe leg-rest to be pivoted relative to the seat pan between a raisedposition and a lowered position; and second pivot means for allowing theseat pan to be pivoted relative to the back-rest; wherein a lockingdrive means is associated with one of said first and second pivot meansfor pivoting relative to each other the components pivoted on said onepivot means, free pivoting is allowed of the components pivoted aboutthe other pivot means and controlling means are provided for controllingthe operation of the locking drive means according to the position ofthe movable portion between the upright and the fully reclinedpositions; wherein as the movable portion is moved between the uprightand fully reclined positions, the locking drive means is controlled suchthat the leg-rest remains in contact with the vehicle floor.
 17. Aseating installation as claimed in claim 16, wherein the back-rest,leg-rest and seat pan of each seating unit define a substantially flatsurface for a passenger to sleep on, when the movable portion isdisposed in the fully reclined position.
 18. A seating installation asclaimed in claim 16, wherein said leg-rest of each seating unitcomprises a linear bearing for facilitating movement of the leg-restover the floor of the vehicle.
 19. A seating installation as claimed inclaim 16, wherein each seating unit further comprises selectivelyoperable driving means for driving the movable portion progressivelybetween the upright and fully reclined positions.
 20. A seatinginstallation as claimed in claim 16, wherein said guiding means of eachseating unit comprises at least one elongate track that is provided onthe fixed portion of the seat, and a track following member provided onthe back-rest, which track following member engages the track forguiding the movable portion between the upright and fully reclinedpositions.
 21. A seating installation as claimed in claim 20, whereinthe back-rest is equipped with a second track following member whichalso engages the track, and is spaced from the first mentioned trackmember along the length of the track, and the track is configured, sothat at each position of the movable portion between the upright andfully reclined positions, the back-rest is located relative to the trackat two spaced locations, thus defining the recline angle of theback-rest.
 22. A seating installation as claimed in claim 19, whereinthe selectively operable driving means comprises a motor that is mountedon the back of the back-rest.
 23. A seating installation as claimed inclaim 16, wherein when the movable portion of one of said seating unitsis disposed in the fully reclined position, the leg rest thereof extendsinto the recess defined by a seating unit in front of said one seatingunit.